/*
 * @(#)ChunkedInputStream.java   0.3-3 06/05/2001
 *
 *  This file is part of the HTTPClient package
 *  Copyright (C) 1996-2001 Ronald Tschal�r
 *
 *  This library is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Lesser General Public
 *  License as published by the Free Software Foundation; either
 *  version 2 of the License, or (at your option) any later version.
 *
 *  This library is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 *  Lesser General Public License for more details.
 *
 *  You should have received a copy of the GNU Lesser General Public
 *  License along with this library; if not, write to the Free
 *  Software Foundation, Inc., 59 Temple Place, Suite 330, Boston,
 *  MA 02111-1307, USA
 *
 *  For questions, suggestions, bug-reports, enhancement-requests etc.
 *  I may be contacted at:
 *
 *  ronald@innovation.ch
 *
 *  The HTTPClient's home page is located at:
 *
 *  http://www.innovation.ch/java/HTTPClient/ 
 *
 */

package org.everrest.http.client;

import java.io.EOFException;
import java.io.FilterInputStream;
import java.io.IOException;
import java.io.InputStream;

/**
 * This class de-chunks an input stream.
 *
 * @author Ronald Tschal�r
 * @version 0.3-3 06/05/2001
 */
class ChunkedInputStream extends FilterInputStream {
    /**
     * @param is
     *         the input stream to dechunk
     */
    ChunkedInputStream(InputStream is) {
        super(is);
    }

    byte[] one = new byte[1];

    public synchronized int read() throws IOException {
        int b = read(one, 0, 1);
        if (b == 1)
            return (one[0] & 0xff);
        else
            return -1;
    }

    private long chunk_len = -1;

    private boolean eof = false;

    public synchronized int read(byte[] buf, int off, int len) throws IOException {
        if (eof)
            return -1;

        if (chunk_len == -1) // it's a new chunk
        {
            try {
                chunk_len = Codecs.getChunkLength(in);
            } catch (ParseException pe) {
                throw new IOException(pe.toString());
            }
        }

        if (chunk_len > 0) // it's data
        {
            if (len > chunk_len)
                len = (int)chunk_len;
            int rcvd = in.read(buf, off, len);
            if (rcvd == -1)
                throw new EOFException("Premature EOF encountered");

            chunk_len -= rcvd;
            if (chunk_len == 0) // got the whole chunk
            {
                in.read(); // CR
                in.read(); // LF
                chunk_len = -1;
            }

            return rcvd;
        } else
        // the footers (trailers)
        {
            // discard
            Request dummy = new Request(null, null, null, null, null, null, false);
            new Response(dummy, null).readTrailers(in);

            eof = true;
            return -1;
        }
    }

    public synchronized long skip(long num) throws IOException {
        byte[] tmp = new byte[(int)num];
        int got = read(tmp, 0, (int)num);

        if (got > 0)
            return (long)got;
        else
            return 0L;
    }

    public synchronized int available() throws IOException {
        if (eof)
            return 0;

        if (chunk_len != -1)
            return (int)chunk_len + in.available();
        else
            return in.available();
    }
}
